Ecology and functional analysis of microbial communities in phytoremediation and grapevine endosphere
The biosphere is dominated by microorganisms and contains about 6×1030 prokaryotic cells. This number represents at least two to three orders of magnitude more than all of the plant and animal cells combined. Microorganisms are highly diverse group of organisms and constitute about 60% of the Earth’s biomass. Microorganisms are key players in important ecological processes such as soil structure formation, decomposition of organic matter and xenobiotics, recycling of essential elements and nutrients, suppressing soil-borne plant diseases and promoting plant growth. An understanding of microbial dynamics and their interactions with biotic and abiotic factors is indispensable in bioremediation techniques, and in biotechnological industries such as pharmaceuticals, food, chemical, and agriculture.
This talk consists of two parts. Fist part is about plant-microbe interactions in phytoremediation of organic and inorganic pollutants. Organic and inorganic pollutants discharged due to accidental or anthropogenic activities, into the environment pose global peril, as they not only ominously threaten human wellbeing, but also have noxious effects on the whole ecosystem. Phytoremediation is highly versatile, solar-driven in situ pollutant extraction system for removal of ecosystem trembling contaminants from soil, water, sediments and air. In phytoremediation plants and their associated microbes work in symbiotic relationship. Different phytoremediation projects were successfully completed for the removal of contaminants. Cultivation-based as well as cultivation-independent analysis techniques were used to study microbial ecology, diversity, colonization and degradation potential. These studies suggested that the application of microbial strains, which are able to compete with the native microflora and to tightly associate with plants, are promising candidates to be used for phytoremediation applications.
Second part deals with microbial endophytic communities associated with grapevine and functional analysis of their interaction with plants. Endophytes, as host-associated microbes, respond to environmental stimuli in a host-mediated fashion. To study how temperature, climate, cultivars and agronomic practices may affect endophytic microbial communities, we studied grapevine-associated microbial populations using a cultivation-independent approach. The plants were sacrificed at sampling; DNA was extracted from roots and stems after surface sterilization and abrasion. Total DNA was extracted and bacterial 16S was PCR amplified and purified. Multiple reactions were pyrosequenced at once using Roche 454 GS FLX+ Titanium technology, using Multiplex Identifiers during PCR. We adopted a DNA-based approach to the analysis of microbial populations’ variation as a response to environmental conditions. Grapevine stems and roots showed complex, rich and distinct endophytic communities. We could clearly identify an intuitive pattern of changes in endophytic microbial composition across temperatures, cultivars and agronomic practices.